[0001] This invention relates to novel organosilicon compounds. More particularly, this
invention relates to organosilicon compounds containing one or two siricon atoms,
at least two silicon-bonded alkoxy groups and at least one group that is bonded to
silicon through oxygen and contains ethylenic unsaturation at a terminal position.
[0002] Certain types of silanes and other organosilicon compounds containing ethylenically
unsaturated radicals bonded to silicon by means of an oxygen atom have been disclosed
in the prior art.
[0003] Reaction products of ethylenically unsaturated epoxide compounds with chlorosilanes
or bis-trichlorosilyl- hydrocarbon compounds of the general formula Cl
3SiQSiCl
3 where Q represents alkylene, alkenylene, arylene or alkarylene are disclosed in United
States Patent No. 3,369,006, which issued to Brown on February 13, 1968. All of these
reaction products contain a silicon-bonded chlorinated alkenyloxy radical of the general
formula YCHCLCH
2OSi, where Y represents an ethylenically unsaturated organic radical containing carbon,
hydrogen and, optionally, oxygen and halogen.
[0004] 1-alkenyloxysilanes wherein an ethylenically unsaturated carbon atom is bonded to
an oxygen atom that is in turn bonded to silicon are disclosed in United States Patent
No. 3,472,888, which issued to Bazouin et al on October 14, 1969, and in British Patent
No. 1,058,866 which issued on February 15, 1967. Bazouin describes vinyloxy- silanes
that are reaction products of a chlorosilane, represented by the formula R
nSiCl
(4-n), with the enol form of an aldehyde or ketone, the enol compound being represented
by the general formula R'R"C=CR"'OH. The products of this reaction exhibit the general
formula
RnSi[O(R"')C=CR'R"] 4-n'
where R represents a monovalent organic radical, and R', R'' and R"' each represent
a hydrogen atom or a monovalent organic radical that is free of reactive substituents.
The compounds described in the British patent can be represented by the same general
formula used for Bazouin's compounds, with the proviso that the radicals represented
by R', R" and R"' optionally contain ethylenic unsaturation which is reactive with
carbon monoxide. The compounds of the British patent are prepared by reacting a terminally
unsaturated hydrocarbon with 1) a silane containing a silicon-bonded hydrogen atom
and 2) carbon monoxide.
[0005] The preparation of allyloxytrimethoxysilane is described by D.F. Peppard in articles
that begin on pages 70 and 73 of volume 68 of the Journal of the American Chemical
Society. The articles were published in 1946. The silane was prepared by reacting
allyl alcohol with trimethoxychlorosilane in the presence of pyridine.
[0006] An objective of this invention is to provide novel silanes and bis-silylhydrocarbons
that contain a plurality of silicon-bonded alkoxy groups and at least one substituent
that is bonded to silicon through oxygen and contains at least four carbon atoms,
two of which form a terminal group of the formula CH
2=CH-.
[0007] A second objective of this invention is to provide novel organosilicon compounds
that will cohesively bond polyoganosiloxane elastomers and resins to inorganic and
organic substrates.
[0008] The novel compounds of this invention include silanes of the general formulae
Formula 1 (R1O)n(R2O)4-n-pR3pSi and
Formula 2 R4[OSi(OR2)3-R3p]2 and organosilicon compounds of the general formulae
Formula 3 (R1O)n(R2O)3-nSiR5Si(OR1)r(OR2)3-r and
Formula 4 R4[OSi(OR2)2R5Si(OR2)3]2 where R1 represents a radical selected from the group consisting of
Formula 5 CH2=CHCH2R6,
Formula 6 CH2=CHR6OR7-,
Formula 7 CH2=CHR6OC(O)R8
Formula 8 CH2=CHR9C(O)OR7, and
Formula 9 (CH2=CHR6O)2R10 ; R2 represents an alkyl radical containing from 1 to 4 carbon atoms; R3 represents a monovalent hydrocarbon or fluorinated hydrocarbon radical; R4 represents a radical selected from the group consisting of



and

R5 represents hydrocarbylene containing at least 2 carbon atoms; R6 represents a hydrocarbylene or substituted hydrocarbylene radical where the substituent
is hydroxyl or alkoxy; R7 is selected from the same group as R6, with the proviso that R7 contains at least 2 carbon atoms; R8 is selected from the same group as R6; R9 represents a radical selected from the same group as R6; R10 represents a trivalent hydrocarbon radical; n is 1 or 2; p is 0 or 1; and r is 0
or 1.
[0009] In preferred embodiments of the present compounds,
R2 is methyl or ethyl, R
3 represents an alkyl, haloalkyl or phenyl, R
5 and R
7 each contain from 2 to 10 carbon atoms, R
8 contains from 1 to 10 carbon atoms, R represents a single bond, alkylene containing
from 1 to 10 carbon atoms, cycloalkylene or phenylene, and R
10 contains from 3 to 10 carbon atoms.
[0010] Compounds of this invention wherein R
2 and
R3 of the foregoing formulae 1-4 are methyl, R is ethylene, n is 1 or 2, p is 0 or 1
and r is 0 constitute a preferred class that is particularly useful as either primers
or adhesion promoters for cohesively bonding polyorganosiloxane elastomers to a variety
of substrates. The silicon-bonded hydrocarbon radicals of the polyorganosiloxane are
preferably methyl.
[0011] The organosilicon compounds of this invention can be defined as silanes, alpha,omega-disilylalkanes,
-disilylcycloalkanes and -disilylarenes that contain at least two silicon-bonded alkoxy
groups per molecule and at least one substituent corresponding to R
1 in the foregoing formulae 1 and 3 or one substituent corresponding to R
4 in formulae 2 and 4.
[0012] R1 is bonded to an oxygen atom that is in turn bonded to silicon and contains at least
four carbon atoms, two of which form an ethylenically unsaturated terminal group of
the formula CH
2=
CH-. The remainder of R
1 is composed of hydrogen and, optionally, oxygen atoms. In one embodiment,
R1 contains two unsaturated terminal groups.
[0013] The substituent identified as R
4 in the preceding formulae 2 and 4 is identical to R
1, except for the fact that it is trivalent and bonded to two silicon-bonded oxygen
atoms.
[0014] The four embodiments of the R
1 and R
4 substituents defined in the preceding formulae 5 through 12 are described in detail
hereinafter. In these embodiments, R is the residue remaining following removal of
a hydroxyl group from one of five classes of organic compounds. R
4 is the residue remaining following removal of two hydroxyl groups from the same classes
of compounds.
[0015] The five classes of organic compounds included within the definitions of the R
1 and R
4 substituents are (1) terminally unsaturated alcohols, (2) phenols containing a terminally
unsaturated aliphatic hydrocarbon radical as a substituent, 3) ethers derived from
the reaction of either (1) or (2) with either a saturated polyhydric alcohol or a
polyhydric phenol, (4) esters derived from the reaction of a terminally unsaturated
carboxylic acid with either a saturated polyhydric alcohol or a polyhydric phenol
and (5) esters derived from the reaction of either (1) or (2) with a saturated aliphatic,
a saturated cycloaliphatic or an aromatic hydroxycarboxylic acid.
[0016] The compounds of this invention can be prepared by reacting one of these five classes
of organic compounds with an alkoxysilane or a bis-silylhydrocarbon containing silicon-bonded
alkoxy groups. The reaction products contain at least two alkoxy groups per silicon
atom.
[0017] If the aforementioned organic and organosilicon compounds are reacted in substantially
equimolar quantities the resultant compound of this invention will be represented
by the foregoing formula 1 or 3, depending upon whether the organosilicon reactant
is a silane or a bis-trialkoxysilyl- hydrocarbon. When one mole of an organic compound
containing two or more hydroxyl groups is present for every two moles of organosilicon
compound, the reaction product will conform to the foregoing formula 2 or 4.
[0018] In one embodiment, referred to hereinafter as A, R is defined as CH
2=CHCH
2R
6-, and R
4 is defined as CH
2=CHR
10=. In these formulae, R
6 is a hydrocarbylene radical that is either unsubstituted or contains at least one
hydroxyl and/or alkoxy group and R
10 is a trivalent hydrocarbon radical.
R6 preferably represents unsubstituted alkylene containing from 1 to 10 or more carbon
atoms, hydroxyl substituted alkylene, hydroxyl substituted alkenylene, unsubstituted
cyclohexylene, unsubstituted phenylene, hydroxyl- or alkoxy substituted phenylene
or the residue remaining following removal of one of the two terminal hydroxyl groups
from a hydroxyl terminated polybutadiene molecule of the formula Formula 16

where q represents an integer from 10 to about 100, inclusive, the value of u is greater
than 0 and the sum of s, t and u is 1. Preferably g is between 50 and 60 and u is
between 0.5 and 1.0.
[0019] In embodiment A, R1 and R
4 represent the residue remaining following removal of one and two hydroxyl groups,
respectively, from either 1) a terminally unsaturated alcohol or 2) a phenol containing
a terminally unsaturated hydrocarbon radical as a substituent. As used in this specification,
the term "terminally unsaturated" implies the presence of a hydrocarbon radical that
includes a CH
2=CH- grouping at a terminal position.
[0020] Terminally unsaturated monohydric alcohols useful for preparing the present compounds
contain at least 4 carbon atoms, and include but are not limited to 3-buten-1-ol,
3-butene-2-ol, 2-methyl-3-butene-2-ol, 5-hexen-1-ol, 9-decene-l-ol, 17-octadecen-l-ol
and the isomeric allyl substituted cyclohexanols.
[0021] Terminally unsaturated polyhydric alcohols or partial ethers thereof can be substituted
for a monofunctional alcohol. It will be understood that a terminally unsaturated
alcohol containing at least two hydroxyl groups or a phenol containing at least two
hydroxyl groups and a terminally unsaturated hydrocarbon radical as substituents must
be used to prepare compounds of this invention corresponding to the foregoing formula
2 or 4.
[0022] Monohydric, terminally unsaturated phenols include the isomeric allyl phenols and
cresols. The definition of R for embodiment A encompasses residues of diphenols, such
as hydroquinone, having as a substituent on the phenyl ring a terminally unsaturated
hydrocarbon radical containing at least 3 carbon atoms. One of the hydroxyl groups
of the diphenol can be reacted to form an ether or ester as, for example, in eugenol.
[0023] In a second embodiment of the present compounds, referred to hereinafter as embodiment
B, R
1 is defined as CH
2=CHR
9C(O)OR
7 and R
4 is defined as CH
2=CHR
9C(O) OR
10.
R7 is selected from the same group of hydrocarbylene radicals as defined hereinabove
for R
6, with the proviso that R
7 contains at least two carbon atoms. R is also selected from the same group of radicals
as R
6 and R
10 represents a trivalent hydrocarbon radical.
[0024] For the compounds of embodiment
B, R and
R4 represent the residues remaining following removal of one and two hydroxyl groups,
respectively, from the alcohol portion of an ester derived from the reaction of a
terminally unsaturated carboxylic acid with either 1) a saturated aliphatic or saturated
cycloaliphatic alcohol containing at least two hydroxyl groups or, 2) a phenol containing
at least two hydroxyl groups. Suitable alcohols and phenols can be represented by
the formula HOR
7OH. Preferably, R
9 represents a single bond and R
7 represents unsubstituted alkylene containing from 2 to 10 carbon atoms, hydroxyl
substituted alkylene containing from 3 to 10 carbon atoms or phenylene, this preference
being based on the availability of the corresponding alcohols and phenols.
[0025] Representative polyhydric alcohols include but are not limited to ethylene glycol,
the isomeric propylene glycols, glycerol, 1,1,1-trimethylolpropane, 1,4-cyclohexanediol
and other alcohols containing at least two hydroxyl groups per molecule and up to
20 or more carbon atoms. Partially etherified polyhydric alcohols containing three
or more hydroxyl groups, at least two of which are unreacted, are also suitable precursors
for the alcohol portion of compounds corresponding to embodiment B. Representative
polyhydroxylated phenols include the aforementioned hydroquinone and resorcinol.
[0026] It will be understood that the alcohol or phenol used to prepare the ester must contain
at least three unreacted hydroxyl groups if the final compound of this invention is
to be represented by the foregoing general formula 2 or 4.
[0027] The aforementioned class of terminally unsaturated carboxylic acids contains from
3 up to 20 or more carbon atoms. Representative members of.this class include acrylic
acid, 3-butenoic acid, 9-decenoic acid and 4-allylbenzoic acid.
[0028] A third embodiment of the present compounds, referred to hereinafter as C, is one
wherein R
1 of the foregoing general formula is·CH
2=CHR
6OR
7, and
R4 is 6 6 7 10 CH
2=CHR
6OR
10. The radicals represented by R
6, R
7 and R
10 are defined in the preceding paragraphs. Preferably, R is an alkylene containing
from 1 to 10 carbon atoms and R
7 is alkylene or hydroxyl substituted alkylene.
[0029] In embodiment C, R and R
4 represent the residues remaining following removal of one and two hydroxyl groups,
respectively, from the saturated polyhydric alcohol or polyhydric phenol portion of
an ether derived from that alcohol or phenol and a terminally unsaturated alcohol
or phenol containing one or more hydroxyl groups. Preferably, the unsaturated alcohol
or phenol is monohydric. The saturated polyhydric alcohol or phenol can be any of
those discussed hereinabove in connection with embodiments A and B, and the terminally
unsaturated alcohol or phenol can likewise be any of those discussed hereinabove in
addition to allyl alcohol. In an alternative of embodiment C, two hydroxyl groups
of a trihydric alcohol such as 1,1,1-trimethylol propane are reacted with a terminally
unsaturated alcohol such as allyl alcohol to form the terminally unsaturated organic
compound. In this alternative embodiment, R is represented by the foregoing general
formula (CH
2=CHR
6O)
2R
10.
[0030] In the fourth embodiment of the present compounds, referred to hereinafter as D,
R
1 of the foregoing general formulae 1 and 3 is defined as CH
2=CHR
6OC(O)R
8- and
R4 of formulae 2 and 4 is defined as CH
2=CHR
6OC(O)R
8R
10. In embodiment D, R represents a hydrocarbylene radical selected from the same group
as previously defined for
R6. Preferably, R represents alkylene containing from 1 to 10 carbon atoms and R
8 represents alkylene containing from 1 to 10 carbon atoms, phenylene, hydroxyl-substituted
phenylene or methoxy substituted phenylene.
[0031] The R
1 and R
4 substituents of the embodiment D represent the residues remaining following removal
of one and two hydroxyl groups, respectively, from the saturated or aromatic hydroxycarboxylic
acid portion of an ester derived from that hydroxycarboxylic acid and any of the terminally
unsaturated alcohols discussed in connection with the preceding embodiments of the
present compounds. It will be understood that the hydroxycarboxylic acid must contain
two or more hydroxyl groups per molecule to prepare a compound of this invention corresponding
to general formula 2 or 4.
[0032] Hydroxcarboxylic acids useful for preparing compounds of embodiment D include but
are not limited to hydroxyacetic acid, lactic acid and the isomeric hydroxybenzoic,
dihydroxybenzoic and dihydroxycinnamic acids.
[0033] Organosilicon compounds corresponding to any of the four embodiments (A-D) of this
invention can be prepared by reacting an alkoxysilane of the general formula

or an alpha,omega-bis-trialkoxysilylhydrocarbon of the general formula

with one of the terminally unsaturated, hydroxylated organic compounds described in
the preceding paragraphs. These organic compounds include terminally unsaturated alcohols,
ethers derived from a terminally unsaturated alcohol and a saturated polyhydric alcohol,
esters derived from a terminally unsaturated carboxylic acid and a saturated polyhydric
alcohol, and esters derived from a terminally unsaturated alcohol and a hydroxycarboxylic
acid.
[0034] The reaction between the organic and organosilicon compounds described hereinbefore
in connection with the various embodiments of the present compounds is conducted under
conditions that are typical for condensation reactions involving alkoxysilanes and
hydroxlated organic compounds. These reactions are usually conducted under an anhydrous
atmosphere such as nitrogen at temperatures from ambient to 200°C. and may employ
a catalyst. Useful catalysts include organic amines, tin compounds and titanium compounds.
Specific catalysts include but are not limited to stannous octoate, dibutyltin dilaurate
and titanium compounds such as tetrabutyl titanate, Ti(OC
4Hg)
4.
[0035] To function effectively the quantity of catalyst present must be soluble in the reaction
mixture. The weight of catalyst typically constitutes from about 0.1 to about 5 percent
of the combined weight of all reactants.
[0036] Reactions involving replacement of silicon-bonded alkoxy groups generate the alcohol
corresponding to the alkoxide group as a by-product under neutral or acidic conditions.
Because these reactions are often reversible, it is usually desirable to remove this
by-product alcohol by distillation as the reaction progresses. The course of the reaction
can then be readily followed by measuring the amount of alcohol collected. Because
methanol and ethanol are the lowest boiling alcohols, it is preferable that the alkoxy
groups of the present organosilicon reactants, represented by OR
2 in the foregoing formulae 1-4, be methoxy or ethoxy.
[0037] The reactants and catalyst are preferably heated at a temperature of from about 50
to 200°C. for a period of time sufficient to achieve a substantially complete reaction,
as indicated by the amount of by-product alcohol collected. This time period is typically
from 1 to about 5 hours.
[0038] Some of the ethylenically unsaturated organic reactants used to prepare the compounds
of this invention will polymerize at the temperatures used to react them with the
organosilicon compound. It may, therefore, be desirable to include in the reaction
mixture an effective amount of a free radical scavenger such as hydroquinone to completely
suppress or at least inhibit polymerization of the organic compound during preparation
of the present compounds.
[0039] Those products of this invention having boiling points below about 200°C. under ambient
or reduced pressure can be isolated by distilling the product from the reaction mixture.
Higher boiling products can be isolated using known chromatographic techniques with
gases or liquids as the carrier.
[0040] For some end use applications of the present compounds, such as primers and adhesion
promoters, the reaction mixture in which the compound is prepared can be used directly
without isolation or purification of the compound.
[0041] In some instances, it may be desirable to include in the reaction mixture a liquid
diluent that may also function as a solvent for the reactants. Suitable diluents include
aliphatic and aromatic hydrocarbons that are liquid at ambient temperature and boil
within the range of from 50 to about 250°C. Representative diluents include hexane,
heptane and liquid aromatic hydrocarbons such as benzene, toluene and xylene.
[0042] An alternate method for preparing the compounds of this invention involves reacting
one of the terminally unsaturated organic compounds described hereinbefore with an
organosilicon compound corresponding to the foregoing general formula 13 or 14, with
the exception that one of the alkoxy groups is replaced with a chlorine atom. The
reaction is typically conducted in the presence of a suitable acid acceptor. The acceptor
can be an organic amine such as pyridine.
[0043] The compounds of this invention contain two different classes of reactive groups,
namely a terminal carbon-to-carbon double bond and at least two silicon-bonded alkoxy
groups. Compounds of this type are suitable for a variety of known end uses, including
moisture activated crosslinking and chain extending agents for hydroxyl containing
polyorganosiloxanes.
[0044] The present compounds will react in the presence of moisture and a suitable catalyst
to yield elastomeric or resinous materials, depending upon the nature of the particular
compound and other reactive materials present in the composition.
[0045] Compounds of this invention wherein
R2 and R 3 of the foregoing formulae 1-4 are methyl, R
5 is ethylene, n is 1 or 2, p is 0 or 1 and r is 0 constitute a preferred class of
compounds that are particularly useful as either primers or adhesion promoters for
achieving cohesive bonding of polyorganosiloxane resins and elastomers to many inorganic
substrates, including glass, steel and aluminum, and to some organic polymers, particularly
the class often referred to as engineering thermoplastics. This class includes polyamides
such as poly(hexamethylene adipamide), polyesters such as poly(ethylene terephthalate),
polyimides and polysulfones.
[0046] Polyorganosiloxane compositions that are curable by a variety of means to yield elastomers
and resins are well known. Room temperature curable compositions can be of two main
types, namely one part compositions curable in the presence of atmospheric moisture
and two part compositions curable by a hydrosilation reaction in the presence of a
platinum group metal or a compound thereof.
[0047] One part room temperature curable polyorganosiloxane compositions typically contain
a hydroxyl terminated polydiorganosiloxane with an average of 50 or more repeating
units per molecule and a crosslinking agent that is typically a silane containing
at least three silicon-bonded alkoxy or other hydrolyzable groups per molecule. A
catalyst such as a compound of tin or titanium is usually present to accelerate the
curing reaction.
[0048] Two part polyorganosiloxane compositions that are curable at room temperature can
contain a liquid or solid polydiorganosiloxane having at least two ethylenically unsaturated
radical such as vinyl per molecule in combination with a crosslinking agent that is
typically an organosilicon compound containing at least three silicon-bonded hydrogen
atoms per molecule. A small amount of platinum'or a platinum compound is usually also
present in these compositions as a hydrosilation catalyst.
[0049] Polyorganosiloxane compositions that cure at elevated temperatures can contain a
polydiorganosiloxane in liquid or solid form in addition to an organic peroxide.
[0050] The aforementioned two part platinum catalyzed polyorganosiloxane compositions that
ordinarily cure at room temperature can be modified to cure only when heated by including
in the composition one of the known platinum catalyst inhibitors. One such class of
inhibitors are the acetylenic alcohols such as 2-methyl-3-butyn-2-ol.
[0051] The curable polyorganosiloxane compositions suitable for use in combination with
the compounds of this invention as primers or adhesion promoters can contain any of
the ingredients conventionally present in these compositions, including fillers, pigments
and flame retardants.
[0052] Curable polyorganosiloxane compositions are sufficiently described in the literature
that a detailed discussion of these compositions in this specification is not required.
[0053] The present adhesion promoters are typically added to a curable polyorganosiloxane
composition in amounts of from 0.1 to about 10 percent by weight, based on the weight
of the total composition. The adhesion promoters are particularly effective in combination
with polyoganosiloxane compositions that are cured by a hydrosilation reaction at
room temperature.
[0054] When used as primers at least one member from the aforementioned class of preferred
compounds of this invention is applied as a thin film to at least one of the surfaces
to be bonded. The compounds can be diluted in a suitable solvent to facilitate their
application to a substrate. Solvents for the present preferred class of compounds
include liquid hydrocarbons such as heptane, benzene, toluene and xylene, and the
methyl and ethyl ethers of either ethylene glycol or propylene glycol.
[0055] Cohesive bonding of polyorganosiloxane elastomers or resins to amorphous or "glassy"
organic polymers such as polymerized esters of acrylic or methacrylic acids, polycarbonates
and polystyrene can be achieved by using the aforementioned preferred class of the
present compounds as primers in combination with copolymers derived from 1) at least
one ethylenically unsaturated organic monomer such as styrene and esters of methacrylic
or acrylic acid, and 2) a silane of the general formula
Formula 17 RSiX3
where R represents vinyl, allyl, or CH
2=CR'C(O)OR", R' is methyl or hydrogen, R'' is alkyl containing from 1 to 4 carbons,
and X represents a hydrolyzable group such as halogen, or lower alkoxy such as methoxy.
These copolymers are disclosed in United States Patent No. 3,306,800 that issued to
E. Plueddemann on February 26, 1967 and is a teaching of primers that are suitable
for use in combination with the present adhesion promoters.
[0056] A particularly preferred class of copolymers is derived from methyl methacrylate
and 3-methacroloxypropyl- trimethoxysilane. The methyl methacrylate constitutes from
5 . to about 95 weight percent of the monomer mixture, preferably from 80 to 95 weight
percent.
[0057] The primer composition also contains a crosslinking agent for the copolymers. Suitable
crosslinking agents include organohydrogensiloxanes containing an average of at least
three silicon-bonded hydrogen atoms per molecule.
[0058] A mixture containing one or more of the copolymers described in the immediately preceding
paragraphs, one or more of the preferred compounds of this invention and a crosslinking
agent is applied as a primer to at least one of the surfaces to be bonded. Alternatively,
one of the preferred compounds of this invention is blended together with a curable
polyorganosiloxane composition, and the copolymer and crosslinking agent are applied
as a thin film to at least one of the surfaces to be bonded.
[0059] The following examples describe preferred embodiments of the present compounds and
demonstrate their utility as adhesion promoters and primers for polyorganosiloxane
compositions. The examples should not be interpreted as limiting the scope of this
invention as defined in the accompanying claims. All parts and percentages disclosed
in the examples are by weight unless otherwise indicated.
[0060] The general method used to prepare the exemplified compounds was to heat a mixture
containing a terminally unsaturated organic reactant, an organosilicon compound and
1 percent of tetrabutyl titanate, based on the total weight of the reaction mixture,
in a reactor equipped to condense and isolate liquid that vaporized from the reaction
mixture. Heating of the reaction mixture was continued until the temperature of the
reaction mixture reached between 100 and 110°C for the silane reactants or from 110
to 166°C for 1,2- bis(trimethoxysilyl)ethane. The amount of by-product alcohol, either
methanol or ethanol, recovered during this heating period was substantially equal
to the calculated value based on the amounts of organosilicon and organic compounds
present.
[0061] The organosilicon compounds used were tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane,
phenyltrimethoxysilane, and l,2-bis(trimethoxysilyl)ethane. Reaction mixtures containing
the four silanes were heated until the temperature of the reaction mixture reached
a value within the range from 100 to 110°C to prevent excessive distillation of silane
from the reaction mixture. Reaction mixtures containing bis(trimethoxysilyl)ethane
could be heated to 160°C. without substantial loss of this reactant by distillation.
Example 1
[0062] Compounds of this invention were prepared by combining a terminally unsaturated organic
compound, an organosilicon compound containing at least three silicon-bonded methoxy
or ethoxy groups per molecule and 1%, based on the total weight of the reaction mixture,
of tetrabutyl titanate. The resultant mixture was heated with stirring while removing
volatile materials by distillation. Heating was continued until an amount of alcohol
equivalent to a substantially complete reaction was isolated from the reaction mixture.
[0063] The types and molar ratios of reactants and the final temperature of the reaction
mixture are listed in Table 1. The reactants used are represented by the following
abbreviations. Unless otherwise indicated, the final temperature of the reaction mixture
was within the range from 100 to 110°C.
Organic Reactants
[0064]

This polymer is available as Poly BD R-45M from Arco Chemicals.
AE 2-Allyloxy-l-ethanol
AP o-Allylphenol
Organosilicon Reactants
[0065]

Example 2
[0066] This example demonstrates the efficacy of representative compounds of this invention
as adhesion promoters for cohesively bonding a polyorganosiloxane elastomer to glass
and metal substrates. A curable, pumpable polyorganosiloxane composition was prepared
by blending the following ingredients to homogeniety:
101.3 parts of a dimethylvinylsiloxy endblocked polydimethylsiloxane having a viscosity
of about 3 Pa.s at 25°C;
34.7 parts of a benzene soluble resinous copolymer containing triorganosiloxy units
and Si02 units in the mol ratio of about 0.7 mol of triorganosiloxy unit per mol of Sio2 unit where the triorganosiloxy units are trimethylsiloxy units and dimethylvinylsiloxy
units and the copolymer contains from 1.4 to 2.2 weight percent of silicon-bonded
vinyl radicals;
48.9 parts of fume silica;
0.7 part of water;
0.31 part of a hydroxyl terminated polydiorganosiloxane containing dimethylsiloxane
and methylvinylsiloxane units about 10 weight percent vinyl radicals and about 16
weight percent hydroxyl radicals;
8.14 part of hexamethyldisilazane;
5.28 parts of a trimethylsiloxy endblocked polydiorganosiloxane having an average
of five methylhydrogensiloxane units and three dimethylsiloxane units per molecule
with a silicon-bonded hydrogen atom content in the range of 0.7 to 0.8 weight percent;
0.15 part of a curing catalyst in the form of a chloroplatinic acid complex of divinyltetramethyldisiloxane
that had been diluted with a liquid dimethylvinylsiloxy terminated polydimethylsiloxane
to achieve 0.7 weight percent platinum; and
0.015 part of 2-methyl-3-butyne-2-ol as a catalyst inhibitor.
Samples of this composition were blended with 1 percent by weight of compounds 1-5
and 7-12 listed in Table 1. A 3.2 mm-thick layer of the resultant composition was
applied as a 2.5 centimeter-wide strip to a glass microscope slide, to sheets of cold-rolled
steel and aluminum, and to brass shim stock. The coated substrate was cured for from
5 to 7 minutes at a temperature of 150°C.
[0067] The adhesion of the elastomer to the substrate was evaluated by loosening one of
the 2.5 cm.- wide edges of the cured coating with a razor blade. A weight of about
0.1 kilogram was attached to this loosened edge strip and allowed to hang free in
an attempt to peel the remainder of the coating from the substrate. The coated surface
was maintained in a substantially horizontal plane and the amount of weight was gradually
increased to 10 kilograms. If the coating separated from the substrate, the weight
(i.e. the force) being applied at the time of failure was recorded, and the failure
was rated an adhesive one. Coatings whic oulc not be peeled from the substrate under
a force of 10 x: were rated as being cohesively bonded to the substrate.
[0068] A substrate coated with a cured elastomer prepared as described in the preceding
paragraph but which did not contain an adhesion promoter was used as a control. The
amount of force, i.e. the amount of weight attached to the coating, being applied
at the time separation of the coating from the substrate occurred was 0.9 kg. for
glass, 0.1 kg. for cold rolled steel, 0.2 kg. for aluminum and 0.5 kg. for brass.
[0069] All of the elastomers with the exception of the one prepared using compound 7 from
Table 1 exhibited cohesive bonding to all substrates. The elastomer prepared using
compound 7 was cohesively bonded to glass and brass, but separated from cold rolled
steel and aluminum under applied weights of 2.5 and 1.6 kg., respectively, which represented
a significant improvement over the control. In all instances, the weight required
to achieve peeling of the control coating from the substrate was less than one kilogram.
Example 3
[0070] This example demonstrates the performance of a primer composition containing one
of the preferred compounds of this invention in combination with a known primer for
adhering inorganic reinforcing agents to organic polymers.
[0071] The primer was prepared by homogeneously blending 2 parts of compound 15 from Table
1 of Example 1, 10 parts of a 20 percent solution in ethyl acetate of a methyl methacrylate/3-methacryloxypropyltrimethoxysilane
copolymer, 87 parts of the monomethyl ether of propylene glycol, and 1 part of a trimethylsiloxy
endblocked polymethylhydrogen- siloxane having a viscosity of about 0.13 Pa.s at 25°C
and a silicon-bonded hydrogen atom content of about 1.6 percent by weight.
[0072] The copolymer was prepared by reacting methyl methacrylate and 3-methacryloxypropyltrimethoxysilane
in a molar ratio of 10:1, respectively, in the presence of 1 percent by weight, based
on total monomers, of 3-mercaptopropyltrimethoxysilane and a catalytic amount of benzoyl
peroxide. The polymerization was conducted in ethyl acetate.
[0073] The ability of the primer to cohesively bond a polydimethylsiloxane elastomer to
both polymethyl methacrylate and a polycarbonate was evaluated using a modification
of ASTM test procedure No. D 1002.
[0074] Samples of polymethyl methacrylate (A) and a polycarbonate (B) in sheet form were
cleaned by wiping them with hexane followed by a wiping with methanol. The samples
measured 2.5 cm in width and 7.6 cm in length. After the samples had dried, a film
of the primer composition was applied by wiping with a clean cloth. The samples were
then allowed to air dry for 20 minutes before a second coating of primer was wiped
on in the same manner as the first coat. After drying in air for 90 minutes, a 2.7
cm.-wide strip of curable polymethylsiloxane elastomer was applied to one end of the
primed surface either sample A or B. One end of the primed surface of the other sample
was placed in contact with opposite surfaces of the elastomer layer to achieve an
overlap of 2.5 cm. between the polycarbonate and polymethylmethacrylate samples. The
elastomer was curable by a platinum catalyzed hydrosilation reaction and exhibited
a durometer of 50 on the Shore A scale following curing.
[0075] The laminate of polycarbonate and polymethyl methacrylate samples separated by the
layer of cured elastomer was placed in a jig that maintained the thickness of the
elastomer layer at 1.3 mm during curing. The resultant assembly was then placed between
the platens ;f a press that was heated to a temperature of 100°C. The platens of the
press were adjusted to maintain a pressure of 313 kPa on the sample for two hours.
The assembly was then removed from the press and allowed to equilibrate under ambient
conditions for at least 16 hours prior to being tested.
[0076] Testing of the samples to determine the strength and nature of the bond between the
elastomer and the two organic polymers was conducted under the conditions specified
in ASTM test procedure No. D 1002. The load at failure and the type of failure were
noted. The three samples tested failed at loads of 2622, 2746 and 2863 kPa. In all
instances, the failure was cohesive, i.e., the elastomer tore while retaining adhesion
to both substrates over the entire contact area.
1. An organosilicon compound of the general formula
where R represents a radical selected from the group consisting of




and

R2 represents an alkyl radical containing from 1 to 4 carbon atoms;
R3 represents a monovalent hydrocarbon or fluorinated hydrocarbon radical;
R4 represents a radical selected from the group consisting of



and

R5 represents hydrocarbylene containing at least 2 carbon atoms;
R6 represents a hydrocarbylene or substituted hydrocarl lene radical where the substituent
is hydroxyl or alkoxy;
R7 is selected from the same group as R6, with the proviso that R7 contains at least 2 carbon atoms;
R8 is selected from the same group as R6;
R9 represents a radical selected from the same group as R6;
R10 represents a trivalent hydrocarbon radical;
n is 1 or 2;
p is 0 or 1;
r is 0 or 1; and
4-n-p is at least 2.
2. A compound according to claim 1 where R2 is methyl or ethyl, R3 represents an alkyl, haloalkyl or phenyl, R5 and R7 each contain from 2 to 10 carbon atoms, R8 contains from 1 to 10 carbon atoms, R9 represents alkylene containing from 1 to 10 carbon atoms, cycloalkylene or phenylene,
and R10 contains from 3 to 10 carbon atoms.
3. A compound according to claim 2 where R3 represents an alkyl radical containing from 1 to 4 carbon atoms, a fluoro substituted
alkyl radical containing from 1 to 4 carbon atoms or a phenyl radical; R5 is ethylene or phenylene; R6 represents alkylene, hydroxyl substituted alkylene, hydroxyl substituted alkenylene,
phenylene or hydroxyl or alkoxy substituted phenylene; R7 is selected from the same group as R6, with the proviso that R7 contains at least 2 carbon atoms; R8 is selected from the same group as R6, R9 represents a radical selected from the same group as R6; and R10 represents an aliphatic hydrocarbon radical, a hydroxyl substituted aliphatic hydrocarbon
radical or an ethylenically unsaturated aliphatic hydrocarbon radical.
4. A compound according to claim 3 where R3 is methyl, phenyl of 3,3,3-trifluoropropyl and n is 1.
5. A compound according to claim 4 where R is CH2=CHCH2R6 , where R6 is alkylene containing from 1 to 10 carbon atoms, hydroxyl substituted alkenylene,
phenylene or alkoxy substituted phenylene.
6. A compound according to claim 5 where R6 is n-octylene, phenylene, methoxy substituted phenylene or the residue remaining
following removal of one terminal hydroxyl group from a hydroxyl terminated polybutadiene
having an average degree of polymerization of between 50 and 60.
7. A compound according to claim 4 where R1 is CH2=CHR6OR7- , where R represents alkylene containing from 1 to 10 carbon atoms and R7 represents an alkylene or a hydroxyl substituted alkylene radical.
8. A compound according to claim 7 where
R6 methylene and R
7 is
9. A compound according to claim 4 where R 1 is CH2=CHR6OC(O)R8-, where R6 represents alkylene containing from 1 to 10 carbon atoms, and R8 represents alkylene containing from 1 to 10 carbon atoms, phenylene, hydroxyl substituted
phenylene or methoxy substituted phenylene.
10. A compound according to claim 4 where R1 is (CH2=CHR6O)2R10 where R10 is a trivalent aliphatic hydrocarbon radical and R6 represents alkylene containing from 1 to 10 carbon atoms.
11. A compound according to claim 10 where R
6 is methylene and
R10 is
12. A compound according to claim 4 where R4 is CH2=CHR10 where R6 is alkylene containing from 1 to 10 carbon atoms and R10 represents a trivalent aliphatic hydrocarbon radical.
13. A composition according to claim 12 where R
6 is methylene and R
10 is
14. A primer composition for adhering a curable polyorganosiloxane elastomer composition
to an inorganic substrate, said primer composition comprising an organosilicon compound
having a general formula selected from the group consisting of

and
where R1 represents a radical selected from the group consisting of




and

R2 and R3 are methyl;
R represents a radical selected from the group consisting of



and

R5 represents ethylene;
R6 represents a hydrocarbylene or substituted hydrocarbylene radical where the substituent
is hydroxyl or alkoxy;
R7 is selected from the same group as R6, with the proviso that R7 contains at least 2 carbon atoms;
R8 is selected from the same group as R6;
R9 represents a radical selected from the same group as R6;
R10 represents a trivalent hydrocarbon radical;
n is 1 or 2;
p is 0 or 1;
r is 0 or 1; and
4-n-p is at least 2.
15. A primer composition according to claim 14 where R6 is alkylene, phenylene, alkoxy substituted phenylene or the residue remaining following
removal of one terminal hydroxyl group from a hydroxyl terminated polybutadiene having
an average degree of polymerization of between 50 and 60.
16. A compound according to claim 14 where R
1 is CH
2=CHR
6OR
7-, R
6 is methylene and R
7 is
17. A primer composition according to claim 14 where R1 is CH2CHR6OC(O)R8, where R6 represents alkylene containing from 1 to 10 carbon atoms, and R8 represents alkylene containing from 1 to 10 carbon atoms, phenylene, hydroxyl substituted
phenylene or methoxy substituted phenylene.
18. A primer composition according to claim 14 where R is CH2=CHR9C(O)OR7-, and where R represents a radical selected from the same group as R6 and R7 represents alkylene containing from 2 to 10 carbon atoms, hydroxyl substituted alkylene
containing from 3 to 10 carbon atoms or phenylene.
19. A primer composition according to claim 14 where R
1 is (CH
2=CHR
6O)
2R
10,
R6 is methylene and
R10 is

20. A primer composition according to claim 14 where R
4 is CH
2=CHR
10, where R
6 is methylene and
R10 is
21. A primer composition according to claim 14 where said primer includes a copol
mer consisting essentially of from 10 to 95 weight percent of repeating units derived
from 3-(methacryloxypropyl)trimethoxysilane and from 5 to 90 percent by weight of
repeating units derived from methyl methacrylate.
22. A primer composition according to claim 21 where said organosilicon compound constitutes
from 40 to 60 weight percent of the combination of said compound and said copolymer.
23. A primer composition according to claim 22 where said organosilicon compound exhibits
the general formula CH
2=CHR
6OR
7- or (CH
2=CHR
6O)
2R
10 where R
6 is methylene, R
7 is

and R
10 is